Dy-doped BiFeO3-PbFeO3-based piezoelectric ceramics for nondestructive testing ultrasonic transducer applications

0.63[0.9BiFeO3–0.1DyFeO3]–0.37PbTiO3 (BDF-PT) multiferroic ceramics with large piezoelectric response (d33 = 88 pC/N) and high Curie temperature (TC = 420 °C) were fabricated around the morphotropic phase boundary through traditional solid-state reaction method. The phase symmetry, microstructure, ferroelectricity and piezoresponse of BDF-PT ceramics were characterized systematically. Based on its high Curie temperature and appropriate piezoelectric properties, the BDF-PT ceramic was used to fabricate nondestructive testing ultrasonic transducer. The Krimholtz, Leedom and Matthaei (KLM) model was applied to design the ultrasonic transducer. The transducer fabricated was characterized to have a center frequency of 7 MHz and a low insertion loss of − 13 dB. This transducer was utilized to test metal stacks with different thicknesses; the experimental results show that the BDF-PT ceramics have great potential for nondestructive testing ultrasonic transducer applications.